Certain three dimensional (3D) information has to be publicly available to reach its target audience, e.g. individual consumers and businesses. For example, 3D information includes images such as schematics of machinery to be used by those who service the machinery which is the subject matter of the schematic. While the 3D information must be available to the public, at the same time, the 3D information needs to be protected to lessen the chances that the 3D information will be used for unintended purposes, including reverse engineering or manufacturing the subject matter of the 3D image.
The 3D information pertaining to a 3D image can be contained in a traditional computer aided design (CAD) file or a reduced, lightweight file format which contains the 3D image but not all of the additional code present in a full CAD file, referred to herein as a native CAD file.
Protecting 3D information is becoming more and more essential as competition moves labor overseas and outsourcing becomes more prevalent. This trend results in the movement of intellectual property into countries which may not support full protection of intellectual property rights or the countries may have local laws and courts which are slow to act to redress improprieties. Further, advances in computer network search engines allows one to locate 3D images on the Internet thereby making those 3D images readily accessible to anyone with a computer and a connection to the Internet.
Systems such as certificates and 3D watermarks are currently being used to add a minimum level of security or protection to the information contained in the 3D image. Unfortunately, these techniques do not prevent industrial reverse engineering, including unauthorized use of the image.
Effective methods of adequately protecting the subject matter of a 3D image/information, e.g. a part, is a complex problem. For example, protecting 3D models which are contained in a native CAD file currently involves restrictions in access to some of the data contained in the native CAD files, creating alternate files which include barriers to prevent reconstruction access to parts of the original 3D CAD models through imports, and creating alternate files with barriers to prevent reconstruction of the original 3D CAD model to other formats supported by a software application.
Original or native CAD files contain a wealth of information, much of which will never be made public. Critical information such as Product Manufacturing Information (PMI) and General Dimensioning & Tolerancing (GD&T) are often stripped from the original CAD file when generating a public version of the 3D information made available to the public.
CAD files are often translated into lightweight files which are typically more compact then the original CAD files. For example, curves and surfaces are replaced by different types of entities depending on the lightweight format, examples of lightweight formats include exact, hybrid and tessellated. Absent fundamentally altering the lightweight image, even if information pertaining to dimensions of the subject matter is truncated when displayed, the geometry and precision can be accessed in different ways. Further, truncation of dimensions or measurements rounded up or down is insufficient to prevent the unauthorized reverse engineering of the subject matter. For example, Acrobat3D® now uses the Okyz® technology to trap the list of graphic primitives as they are sent to the graphic card. This enables Acrobat3D® to read any Open GL-based model with a good accuracy. A similar approach can be successfully accomplished with DWF Writer®. An unauthorized individual wishing to reverse engineer the product can measure each part, one by one, by displaying the model at a very large scale with the zoom functions found in most software applications, when dimensions are made unavailable.
Further, conventional authorizing software applications, e.g. 3D Studio Max®, can open export CAD data in the form of a lightweight model, to enable the complete reading of the original lightweight model.
One recent method for protecting the intellectual property of a 3D image or shape, such as copyrighted data, is provided by U.S. Pat. No. 6,678,378 ('378). The '378 patent is directed to an encryption and de-encryption method for limiting unauthorized access to a 3D shape. The '378 method of encryption prevents unauthorized access to the image without entering a password or key to de-encrypt the encrypted file. Further, the encrypted file alters the original 3D shape data such that the encrypted 3D object can not be displayed in a meaningful way on a computer screen or the like. Thus, the encrypted file is useless to anyone who does not have access to the password or a method of de-encrypting the encrypted file.
There is a need in the art for new methods of protecting 3D images which allow one to distribute the images and/or make the available to the public for viewing in substantially the original 3D form, while protecting the intellectual property contained within the 3D image.